Patients with congenital and acquired heart disease are exposed to a lifelong thromboembolic risk that increases progressively from adolescence to adulthood because of residual lesions, arrhythmias, venous congestion, repeated interventions and acquired co-morbidities. Management is further complicated by concurrent bleeding risk. To provide practical expert consensus recommendations on thromboprophylaxis in congenital and acquired heart disease from adolescence to adulthood. A multidisciplinary expert panel from the Paediatric and Congenital Cardiology Branch of the French Society of Cardiology conducted a focused literature review and structured consensus process. Recommendations were graded pragmatically according to available evidence and expert agreement. Major clinical scenarios include Fontan circulation, Eisenmenger syndrome and Kawasaki coronary sequelae. From adolescence, bleeding risk may increase in girls and women as a result of dysovulation, menstruation and anticoagulant-related uterine bleeding, warranting gynaecological referral. In adulthood, thrombotic burden progressively increases through cumulative exposure to arrhythmias and reinterventions, such as transcatheter pulmonary valve replacement. Management should therefore rely on individualized treatment integrating thrombosis-bleeding balance, serial reassessment, patient education and tailored choice among antiplatelet therapy, vitamin K antagonists and direct oral anticoagulants. Thromboprophylaxis from adolescence to adulthood should move towards lifelong personalized care based on cumulative risk exposure, changing clinical status and sex-specific issues. Large prospective studies are required to refine risk stratification and optimize treatment pathways.